# Propagation Constant Measurement Based on a Single Transmission Line Standard Using a Two-port VNA

## TL;DR

This paper introduces a novel method for accurately measuring the propagation constant of transmission lines using a single standard and a two-port VNA without prior calibration, enhancing broadband traceability and reducing measurement errors.

## Contribution

The method allows propagation constant measurement with a single line standard and no prior VNA calibration, improving accuracy and repeatability.

## Key findings

- Measurements on a slab coaxial airline were consistent across three VNAs.
- The method eliminates connector-related errors by avoiding cable disconnection.
- Results demonstrate nearly identical propagation constants across different VNAs.

## Abstract

This study presents a new method for measuring the propagation constant of transmission lines using a single line standard and without prior calibration of a two-port vector network analyzer (VNA). The method provides accurate results by emulating multiple line standards of the multiline calibration method. Each line standard is realized by sweeping an unknown network along a transmission line. The network need not be symmetric or reciprocal, but must exhibit both transmission and reflection. We performed measurements using a slab coaxial airline and repeated the measurements on three different VNAs. The measured propagation constant of the slab coaxial airline from all VNAs is nearly identical. By avoiding disconnecting or moving the cables, the proposed method eliminates errors related to repeatability of connectors, resulting in improved broadband traceability to SI units.